焊接不(bu)銹鋼異徑(jing)管的一般要求有以下幾點:


  ①. 焊(han)制異徑管的(de)圓(yuan)度不應(ying)大于各(ge)端外徑的(de)1%,且不大于5mm.


  ②. 同心(xin)異徑(jing)管兩端中心(xin)線(xian)應(ying)重合,其偏心(xin)值(a1-a2)/2(符號見圖2-50)不應(ying)大(da)(da)于(yu)大(da)(da)端外徑(jing)的1%,且(qie)不應(ying)大(da)(da)于(yu)5mm;偏心(xin)異徑(jing)管過(guo)渡區應(ying)圓(yuan)滑。


圖 50.jpg


1. 同心異徑(jing)管展(zhan)開圖


   圖(tu)(tu)2-51為(wei)同心異(yi)徑管展開圖(tu)(tu),其作(zuo)圖(tu)(tu)步驟如(ru)下。


圖 51.jpg


  ①. 按(an)已知尺寸畫(hua)出主視圖和俯(fu)視圖,將(jiang)其上、下口分成(cheng)12等份(fen),使表面(mian)組成(cheng)24個(ge)三角形。


  ②. 采(cai)用直角三角形法(fa)求出1-2'線的實長。


  ③. 按照已知三(san)邊作(zuo)三(san)角(jiao)形的(de)方法,即可(ke)得(de)到同心異徑管的(de)展開圖。



 2. 不銹鋼異徑管(guan)的制作(zuo)


  不銹鋼異徑管分同心和偏心兩種(zhong),可用卷(juan)焊、摔制、抽條等方(fang)法(fa)制作。


  采用(yong)(yong)(yong)(yong)鋼板(ban)(ban)(ban)卷焊時,先作出樣(yang)板(ban)(ban)(ban),然(ran)后將樣(yang)板(ban)(ban)(ban)平鋪在鋼板(ban)(ban)(ban)上劃線、下料(liao),并按(an)要(yao)求(qiu)加工(gong)坡(po)口(kou)(kou),除去毛刺和氧化鐵皮,用(yong)(yong)(yong)(yong)滾板(ban)(ban)(ban)機(ji)或壓力(li)機(ji)卷圓(yuan)(yuan),再用(yong)(yong)(yong)(yong)1/4圓(yuan)(yuan)的(de)(de)弧形(xing)(xing)樣(yang)板(ban)(ban)(ban)檢(jian)查(cha)內圓(yuan)(yuan)的(de)(de)弧度。經修理達(da)到要(yao)求(qiu)后施焊。無機(ji)械卷圓(yuan)(yuan)時,也(ye)可用(yong)(yong)(yong)(yong)手(shou)工(gong)卷制,如圖2-52所示。制作時,先在切割(ge)好的(de)(de)鋼板(ban)(ban)(ban)上分區域劃線條,按(an)區向(xiang)內敲打彎制,錘擊力(li)量要(yao)適當,以免用(yong)(yong)(yong)(yong)力(li)過大鋼板(ban)(ban)(ban)產生(sheng)過度變形(xing)(xing),并隨時用(yong)(yong)(yong)(yong)1/4圓(yuan)(yuan)弧形(xing)(xing)樣(yang)板(ban)(ban)(ban)檢(jian)查(cha);發現扭(niu)曲不對口(kou)(kou)時,可用(yong)(yong)(yong)(yong)工(gong)具校正(zheng)。


圖 52.jpg


  當管(guan)(guan)徑較(jiao)小、采(cai)用(yong)(yong)鋼(gang)板卷制(zhi)有困(kun)難(nan)時(shi),異(yi)徑管(guan)(guan)可用(yong)(yong)鋼(gang)管(guan)(guan)摔(shuai)(shuai)制(zhi)。制(zhi)作時(shi),先用(yong)(yong)烘爐(lu)或氧(yang)-乙(yi)炔焰將管(guan)(guan)子加(jia)熱到(dao)800~950℃.摔(shuai)(shuai)同心異(yi)徑管(guan)(guan)時(shi),邊(bian)錘擊(ji)邊(bian)轉動(dong)管(guan)(guan)子,由大(da)到(dao)小,使管(guan)(guan)面(mian)圓弧(hu)均勻過渡,錘面(mian)要(yao)放平,防止(zhi)錘擊(ji)時(shi)使管(guan)(guan)壁產生麻面(mian)。一遍摔(shuai)(shuai)不好時(shi),可再加(jia)熱,直到(dao)摔(shuai)(shuai)成為止(zhi)。摔(shuai)(shuai)偏(pian)心大(da)小頭時(shi),管(guan)(guan)下(xia)壁不應加(jia)熱,采(cai)用(yong)(yong)烘爐(lu)加(jia)熱時(shi),可用(yong)(yong)水將管(guan)(guan)下(xia)壁冷卻后再摔(shuai)(shuai)管(guan)(guan)。摔(shuai)(shuai)制(zhi)時(shi),應左(zuo)右轉動(dong),使其過渡圓滑。


制作異徑管(guan)時,其(qi)變徑過渡(du)區的長度視管(guan)徑不同(tong)而異,為減小局(ju)部阻力,一般不應小于大管(guan)外徑。